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International Journal of Molecular... Sep 2021Anti-epileptic drugs (AEDs) are an important group of drugs of several generations, ranging from the oldest phenobarbital (1912) to the most recent cenobamate (2019).... (Review)
Review
Anti-epileptic drugs (AEDs) are an important group of drugs of several generations, ranging from the oldest phenobarbital (1912) to the most recent cenobamate (2019). Cannabidiol (CBD) is increasingly used to treat epilepsy. The outbreak of the SARS-CoV-2 pandemic in 2019 created new challenges in the effective treatment of epilepsy in COVID-19 patients. The purpose of this review is to present data from the last few years on drug-drug interactions among of AEDs, as well as AEDs with other drugs, nutrients and food. Literature data was collected mainly in PubMed, as well as google base. The most important pharmacokinetic parameters of the chosen 29 AEDs, mechanism of action and clinical application, as well as their biotransformation, are presented. We pay a special attention to the new potential interactions of the applied first-generation AEDs (carbamazepine, oxcarbazepine, phenytoin, phenobarbital and primidone), on decreased concentration of some medications (atazanavir and remdesivir), or their compositions (darunavir/cobicistat and lopinavir/ritonavir) used in the treatment of COVID-19 patients. CBD interactions with AEDs are clearly defined. In addition, nutrients, as well as diet, cause changes in pharmacokinetics of some AEDs. The understanding of the pharmacokinetic interactions of the AEDs seems to be important in effective management of epilepsy.
Topics: Anticonvulsants; COVID-19; Cannabidiol; Carbamazepine; Clobazam; Drug Interactions; Epilepsy; Humans; Nutrients; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 34502487
DOI: 10.3390/ijms22179582 -
Clinical Chemistry and Laboratory... Jun 2024Primidone is an anticonvulsive drug used in the treatment of epilepsy and essential tremor. It offers beneficial effects in controlling seizures, but its usage is...
An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure (RMP) for the quantification of primidone in human serum and plasma.
OBJECTIVES
Primidone is an anticonvulsive drug used in the treatment of epilepsy and essential tremor. It offers beneficial effects in controlling seizures, but its usage is also associated with possible side effects. To ensure optimal therapy, it is crucial to measure its concentration through accurate quantification methods. Therefore, our main goal was to develop and validate a new reference measurement procedure (RMP) for accurately measuring primidone levels in human serum and plasma.
METHODS
In our study, we focused on the separation of primidone from both known and unknown interferences using a C18 column. To achieve accurate sample preparation, we developed a protocol involving protein precipitation followed by a high dilution step. The validation of the assay and determination of measurement uncertainty were carried out following guidelines from organizations such as the Clinical and Laboratory Standards Institute, the International Conference on Harmonization, and the Guide to the Expression of Uncertainty in Measurement. These rigorous validation processes ensure the reliability and accuracy of our method for quantifying primidone levels in human serum and plasma samples.
RESULTS
The RMP was shown to be highly selective and specific, with no evidence of matrix interference. It can be used to quantify primidone in the range of 0.150-30.0 μg/mL. Intermediate precision was less than 4.0 %, and repeatability CV ranged from 1.0 to 3.3 % across all concentration levels. The relative mean bias ranged from 0.1 to 3.9 % for native serum levels, and from -2.6 to 2.8 % for lithium-heparin plasma levels. The measurement uncertainties for single measurements and target value assignment were 1.5-4.1 % and 0.9-1.0 %, respectively.
CONCLUSIONS
In this study, we introduce an innovative LC-MS/MS-based candidate RMP specifically designed for primidone in human serum and plasma. Our RMP offers a traceable platform, facilitating the standardization of routine assays and enabling the evaluation of clinically relevant samples. With this novel approach, we aim to enhance the accuracy and reliability of primidone measurements, ultimately benefiting the field of clinical research and patient care.
Topics: Humans; Tandem Mass Spectrometry; Primidone; Chromatography, Liquid; Reference Standards; Reproducibility of Results; Indicator Dilution Techniques; Limit of Detection; Anticonvulsants; Liquid Chromatography-Mass Spectrometry
PubMed: 38549258
DOI: 10.1515/cclm-2023-1032 -
Clinical Neuropharmacology 2016It is not known whether current use of the medication primidone affects brain γ-aminobutyric acid (GABA) concentrations. This is an important potential confound in...
OBJECTIVES
It is not known whether current use of the medication primidone affects brain γ-aminobutyric acid (GABA) concentrations. This is an important potential confound in studies of the pathophysiology of essential tremor (ET), one of the most common neurological diseases. We compared GABA concentrations in the dentate nucleus in 6 ET patients taking primidone versus 26 ET patients not taking primidone.
METHODS
(1)H magnetic resonance spectroscopy was performed using a 3.0-T Siemens Tim Trio scanner. The MEGA-PRESS J-editing sequence was used for GABA detection in 2 cerebellar volumes of interest (left and right) that included the dentate nucleus.
RESULTS
The right dentate GABA concentration was similar in the 2 groups (2.21 ± 0.46 [on primidone] vs 1.93 ± 0.39 [not on primidone], P = 0.15), as was the left dentate GABA concentration (1.61 ± 0.35 [on primidone] vs 1.67 ± 0.34 [not on primidone], P = 0.72). The daily primidone dose was not associated with either right or left dentate GABA concentrations (P = 0.89 and 0.76, respectively).
CONCLUSIONS
We did not find a difference in dentate GABA concentrations between 6 ET patients taking daily primidone and 26 ET patients not taking primidone. Furthermore, there was no association between daily primidone dose and dentate GABA concentration. These data suggest that it is not necessary to exclude ET patients on primidone from magnetic resonance spectroscopy studies of dentate GABA concentration, and if assessment of these concentrations was to be developed as a biomarker for ET, primidone usage would not confound interpretation of the results.
Topics: Aged; Aged, 80 and over; Anticonvulsants; Cerebellar Nuclei; Dose-Response Relationship, Drug; Essential Tremor; Female; Humans; Magnetic Resonance Imaging; Male; Primidone; Protein Binding; Severity of Illness Index; gamma-Aminobutyric Acid
PubMed: 26757316
DOI: 10.1097/WNF.0000000000000127 -
Seizure Nov 2019Adverse cutaneous reactions caused by mostly aromatic antiepileptic drugs (AED) affect 50.000 people a year in the United Kingdom (UK; incidence 75.7/100.000). Optimal... (Review)
Review
Adverse cutaneous reactions caused by mostly aromatic antiepileptic drugs (AED) affect 50.000 people a year in the United Kingdom (UK; incidence 75.7/100.000). Optimal management of these cases is often difficult, as the patient may report symptoms to a general practitioner, attend Accident & Emergency or inform a specialist over the telephone or via email. When clinical assessment is limited it is thought safest to withdraw offending medication and inform the patient of a new drug allergy. This may unjustifiably restrict future treatment choices, and increase cost. Most frequent offenders are aromatic AEDs: carbamazepine, oxcarbazepine, eslicarbazepine, phenytoin, lamotrigine, phenobarbitone, primidone (recently licensed lacosamide associated with lower risk) and the sulpha-derivative zonisamide. Our study provides a summary of severe delayed allergic reactions and offers a pragmatic management pathway for patients suffering a suspected drug-induced rash. We include UK pretreatment screening guidelines, step by step clinical assessment of rash and associated symptoms aiding early identification of patients at risk of developing severe allergic reactions. At the same time our manuscript reviews published data informing best choice and titration of alternative medication when allergy confirmed. Finally we summarize current knowledge on genetic predisposition and other personalized risks of AED allergies identifying gaps in our current understanding.
Topics: Adult; Ambulatory Care; Anticonvulsants; Disease Management; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Epilepsy; Humans; Risk Factors; Stevens-Johnson Syndrome
PubMed: 31708349
DOI: 10.1016/j.seizure.2019.07.003 -
Annals of Neurology Nov 2018A recent study observed a 2-fold greater risk of Parkinson disease (PD) in relation to the β2-adrenoreceptor antagonist propranolol and a markedly lower risk of PD for...
OBJECTIVE
A recent study observed a 2-fold greater risk of Parkinson disease (PD) in relation to the β2-adrenoreceptor antagonist propranolol and a markedly lower risk of PD for the β2-adrenoreceptor agonist salbutamol. We examined whether confounding by clinical indication for these medications, that is, tremor and smoking-related pulmonary conditions, explained these associations.
METHODS
In a large, population-based case-control study of United States Medicare beneficiaries in 2009 with diagnosis codes, procedure codes, and prescription data (48,295 incident PD cases, 52,324 controls), we examined the risk of PD in relation to use of selected β antagonists (propranolol, carvedilol, metoprolol), the β2 agonist salbutamol, and other medications used for the same clinical indications (primidone, inhaled corticosteroids). We adjusted for demographics, smoking, and overall use of medical care. We then examined the effect of also adjusting for clinical indication and applying medication exposure lagging.
RESULTS
Propranolol appeared to increase PD risk (odds ratio [OR] = 3.62, 95% confidence interval [CI] = 3.31-3.96). When we adjusted for tremor or abnormal involuntary movement prior to the PD diagnosis/reference date and lagged propranolol exposure, the association was 0.97 (95% CI = 0.80-1.18). Primidone, also used for tremor, was similarly sensitive to this adjustment and lagging. β Antagonists not indicated for tremor appeared to reduce PD risk (carvedilol: OR = 0.77, 95% CI = 0.73-0.81; metoprolol: OR = 0.94, 95% CI = 0.91-0.97) and were insensitive to adjustment for indications and lagging. Neither salbutamol nor inhaled corticosteroids were consistently associated with PD risk.
INTERPRETATION
β2-adrenoreceptor agonists and antagonists do not appear to alter PD risk. Ann Neurol 2018;84:691-701.
Topics: Adrenergic beta-2 Receptor Agonists; Adrenergic beta-Antagonists; Aged; Case-Control Studies; Female; Humans; Male; Parkinson Disease
PubMed: 30225948
DOI: 10.1002/ana.25341 -
Epilepsy Currents 2022: Enzyme-inducing antiseizure medications (eiASMs) have been hypothesized to be associated with long-term risks of cardiovascular disease. : To quantify and model the...
: Enzyme-inducing antiseizure medications (eiASMs) have been hypothesized to be associated with long-term risks of cardiovascular disease. : To quantify and model the putative hazard of cardiovascular disease secondary to eiASM use. : This cohort study covered January 1990 to March 2019 (median [IQR] follow-up, 9 [4-15], years). The study linked primary care and hospital electronic health records at National Health Service hospitals in England. People aged 18 years or older diagnosed as having epilepsy after January 1, 1990, were included. All eligible patients were included with a waiver of consent. No patients were approached who withdrew consent. Analysis began January 2021 and ended August 2021. : Receipt of 4 consecutive EI ASMs (carbamazepine, eslicarbazepine, oxcarbazepine, phenobarbital, phenytoin, primidone, rufinamide, or topiramate) following an adult-onset (age >/=18 years) epilepsy diagnosis or repeated exposure in a weighted cumulative exposure model. : Three cohorts were isolated, 1 of which comprised all adults meeting a case definition for epilepsy diagnosed after 1990, 1 comprised incident cases diagnosed after 1998 (hospital linkage date), and 1 was limited to adults diagnosed with epilepsy at 65 years or older. Outcome was incident cardiovascular disease (ischemic heart disease or ischemic or hemorrhagic stroke). Hazard of incident cardiovascular disease was evaluated using adjusted propensity-matched survival analyses and weighted cumulative exposure models. : Of 10,916,166 adults, 50,888 (.6%) were identified as having period-prevalent cases (median [IQR] age, 32 [19-50] years; 16 584 [53%] female), of whom 31,479 (62%) were diagnosed on or after 1990 and were free of cardiovascular disease at baseline. In a propensity-matched Cox proportional hazards model adjusted for age, sex, baseline socioeconomic status, and cardiovascular risk factors, the hazard ratio for incident cardiovascular disease was 1.21 (95% CI, 1.06-1.39) for those receiving eiASMs. The absolute difference in cumulative hazard diverges by more than 1% and greater after 10 years. For those with persistent exposure beyond 4 prescriptions, the median hazard ratio increased from a median (IQR) of 1.54 (1.28-1.79) when taking a relative defined daily dose of an eiASM of 1 to 2.38 (1.52-3.56) with a relative defined daily dose of 2 throughout a maximum of 25 years' follow-up compared with those not receiving an eiASM. The hazard was elevated but attenuated when restricting analyses to incident cases or those diagnosed when older than 65 years. : The hazard of incident cardiovascular disease is higher in those receiving eiASMs. The association is dose dependent and the absolute difference in hazard seems to reach clinical significance by approximately 10 years from first exposure.
PubMed: 35444497
DOI: 10.1177/15357597211070392 -
Neurological Research and Practice 2020Management of primary orthostatic tremor (POT) remains challenging, and medication is often ineffective. We report the case of a 53-year-old female with orthostatic...
Management of primary orthostatic tremor (POT) remains challenging, and medication is often ineffective. We report the case of a 53-year-old female with orthostatic tremor for 6 years who was refractory to gabapentin, clonazepam, primidone and propranolol. After treatment with 4 mg/day perampanel, she reported almost complete resolution of tremor. The diagnosis of POT was confirmed by tremor analysis using surface electromyography. Our report shows the potential use of the novel AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor antagonist perampanel for the treatment of POT. To date, only two similar patients, one refractory to treatment and the other previously treated with clonazepam only, have been reported. We would like to note that our patient was refractory to all previous therapy and responded to a low dose of perampanel without side effects. The striking clinical improvement suggests a putative role of glutamate in the pathophysiology of orthostatic tremor.
PubMed: 33324909
DOI: 10.1186/s42466-020-0050-0 -
Movement Disorders Clinical Practice 2017The objective of this study was to characterize the clinical features, course, and treatment of essential tremor (ET) in children.
BACKGROUND
The objective of this study was to characterize the clinical features, course, and treatment of essential tremor (ET) in children.
METHODS
A retrospective chart review was conducted over 25 years (1984-2011). Inclusion criteria were age <21 years and satisfying the core diagnostic criteria for ET. Primary exclusion criteria included other neurological findings, tremorogenic medications, sudden onset/stepwise progression, primary orthostatic tremor, and isolated task specificity; and secondary exclusion criteria were abnormal neuroimaging or metabolic/thyroid studies. Cases were reviewed for age, sex, family history, tremor characteristics, functional impairment, treatment, and follow-up.
RESULTS
In total, 211 children had ET, including 130 males and 81 females. The mean ± standard deviation age was at diagnosis was 14.09 ± 5.0 years, the age of onset was 9.71 ± 5.62 years, and the age of onset was birth in 7 children. One hundred ninety-nine children had bilateral hand tremor, 34 had asymmetry, 9 had unilateral onset but later became bilateral. Twelve children had voice tremors, 13 had leg tremors, 5 had head tremors, and 7 had trunk tremors. Tremor at rest was present in 20 children. Thirty-five percent of the children had a family history of ET, including in a father (n = 21), mother (n = 13), brother (n = 6), sister (n = 3), and other family member (n = 28). Fifty-five percent of patients had functional disabilities, including writing (n = 66), eating (n = 28) drinking from a cup (n = 13), typing (n = 4), playing instruments (n = 6), buttoning (n = 6), and playing (n = 3). For treatment, 33 patients received propranolol, 1 received atenolol, 13 received primidone, 3 received metoprolol, and 1 received nadolol. In total, 99 patients were followed for a mean ± standard deviation of 1.82 ± 2.21 years.If left untreated, tremor remained unchanged in 33 patients, and 7 had an apparent short-term improvement. On propranolol, 15 of 20 patients significantly improved.
CONCLUSIONS
This is the largest series to date of ET in children. The current findings indicate that onset at birth is possible, family history is less common in children than in adults, and tremor at rest is possible. Functional disability was noted in 55% of children, and 29.4% required medication.
PubMed: 30363473
DOI: 10.1002/mdc3.12385 -
Clinical Pharmacokinetics Sep 2022Ritonavir-boosted nirmatrelvir (RBN) has been authorized recently in several countries as an orally active anti-SARS-CoV-2 treatment for patients at high risk of... (Review)
Review
Clinically Relevant Interactions Between Ritonavir-Boosted Nirmatrelvir and Concomitant Antiseizure Medications: Implications for the Management of COVID-19 in Patients with Epilepsy.
Ritonavir-boosted nirmatrelvir (RBN) has been authorized recently in several countries as an orally active anti-SARS-CoV-2 treatment for patients at high risk of progressing to severe COVID-19 disease. Nirmatrelvir is the active component against the SARS-CoV-2 virus, whereas ritonavir, a potent CYP3A inhibitor, is intended to boost the activity of nirmatrelvir by increasing its concentration in plasma to ensure persistence of antiviral concentrations during the 12-hour dosing interval. RBN is involved in many clinically important drug-drug interactions both as perpetrator and as victim, which can complicate its use in patients treated with antiseizure medications (ASMs). Interactions between RBN and ASMs are bidirectional. As perpetrator, RBN may increase the plasma concentration of a number of ASMs that are CYP3A4 substrates, possibly leading to toxicity. As victims, both nirmatrelvir and ritonavir are subject to metabolic induction by concomitant treatment with potent enzyme-inducing ASMs (carbamazepine, phenytoin, phenobarbital and primidone). According to US and European prescribing information, treatment with these ASMs is a contraindication to the use of RBN. Although remdesivir is a valuable alternative to RBN, it may not be readily accessible in some settings due to cost and/or need for intravenous administration. If remdesivir is not an appropriate option, either bebtelovimab or molnupiravir may be considered. However, evidence about the clinical efficacy of bebtelovimab is still limited, and molnupiravir, the only orally active alternative, is deemed to have appreciably lower efficacy than RBN and remdesivir.
Topics: Antibodies, Neutralizing; Antiviral Agents; Epilepsy; Humans; Ritonavir; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 35895276
DOI: 10.1007/s40262-022-01152-z -
The Journal of Neuroscience : the... Mar 2021Transient receptor potential melastatin 3 (TRPM3) is a heat-activated ion channel in primary sensory neurons of the dorsal root ganglia (DRGs). Pharmacological and...
Transient receptor potential melastatin 3 (TRPM3) is a heat-activated ion channel in primary sensory neurons of the dorsal root ganglia (DRGs). Pharmacological and genetic studies implicated TRPM3 in various pain modalities, but TRPM3 inhibitors were not validated in TRPM3 mice. Here we tested two inhibitors of TRPM3 in male and female wild-type and TRPM3 mice in nerve injury-induced neuropathic pain. We found that intraperitoneal injection of either isosakuranetin or primidone reduced heat hypersensitivity induced by chronic constriction injury (CCI) of the sciatic nerve in wild-type, but not in TRPM3 mice. Primidone was also effective when injected locally in the hindpaw or intrathecally. Consistently, intrathecal injection of the TRPM3 agonist CIM0216 reduced paw withdrawal latency to radiant heat in wild-type, but not in TRPM3 mice. Intraperitoneal injection of 2 mg/kg, but not 0.5 mg/kg isosakuranetin, inhibited cold and mechanical hypersensitivity in CCI, both in wild-type and TRPM3 mice, indicating a dose-dependent off-target effect. Primidone had no effect on cold sensitivity, and only a marginal effect on mechanical hypersensitivity. Genetic deletion or inhibitors of TRPM3 reduced the increase in the levels of the early genes c-Fos and pERK in the spinal cord and DRGs in CCI mice, suggesting spontaneous activity of the channel. Intraperitoneal isosakuranetin also inhibited spontaneous pain related behavior in CCI in the conditioned place preference assay, and this effect was eliminated in TRPM3 mice. Overall, our data indicate a role of TRPM3 in heat hypersensitivity and in spontaneous pain after nerve injury. Neuropathic pain is a major unsolved medical problem. The heat-activated TRPM3 ion channel is a potential target for novel pain medications, but the pain modalities in which it plays a role are not clear. Here we used a combination of genetic and pharmacological tools to assess the role of this channel in spontaneous pain, heat, cold, and mechanical hypersensitivity in a nerve injury model of neuropathic pain in mice. Our findings indicate a role for TRPM3 in heat hyperalgesia, and spontaneous pain, but not in cold and mechanical hypersensitivity. We also find that not only TRPM3 located in the peripheral nerve termini, but also TRPM3 in the spinal cord or proximal segments of DRG neurons are important for heat hypersensitivity.
Topics: Animals; Female; Hot Temperature; Hyperalgesia; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neuralgia; Peripheral Nerve Injuries; TRPM Cation Channels
PubMed: 33478988
DOI: 10.1523/JNEUROSCI.1551-20.2020